usbHSM - a consumer available, low cost hardware security module

[Legit-Design]

Well if you make a prototype now and keep it on the backburner and do it while you have time and resources. Then maybe in the future you will have something to show and people will know what they are signing up for?
Why not spend time and try do it in the small scale first. Like what Dave is doing he talks about it in the The Amp Hour and all the time, make a run of the 10 boards if there is interest scale it up gradually, don't try to make it big the first time. If you can't do it on the small scale find a project that can be done without spending thousands in advance?